Should I change motors ?

[JohnnieB]

Sounds like you have a series cart (Series wound motor) tall tires and a high speed motor. Plus a sick or inadequate battery pack and a sick or inadequate charger.

Tall tires draw more amps than stock height (18") tires and high speed motors draw more amps than standard speed motors, so a higher capacity battery pack is needed to provide the more Amps needed for the double whammy.

What is the Amp-Hour rating of the batteries? (225AH is standard for a 36V pack)

The charge time mentioned (16-24 Hours) is excessive, so something is amiss with the batteries and/or the charger.

What charger is being used?

BTW - The DVM type battery meter does give you some very useful information, you just have to learn when to read it and what it means.